PHOENIX (AP) — The union representing Arizona teachers on Tuesday slammed Gov. Doug Ducey for vetoing what they called a sensible change to the evaluation process for classroom instructors and principals.

The bill Ducey vetoed would have lowered the percentage of a teacher’s performance evaluation based on standardized test scores and excluded students who weren’t in a teacher’s class the entire year. It also would have barred use of test scores if the teacher doesn’t teach courses covered by the tests.

Ducey said in a veto letter that the legislation would have diminished the “impact and focus of improving student academic outcomes as a measurement of quality teaching and learning.”